Soap bars

ABSTRACT

A detergent bar including a major amount of anhydrous watersoluble higher fatty acid soap and a minor amount of a watersoluble synthetic detergent chosen from the group including fatty ester amides of sulphosuccinic acid.

0 llmted States Patent [191 {111 3,793,215

Smith Feb. 19, 1974 [54] SOAP BARS 3,247,121 4/1966 Hendricks 252/177 3,076,766 2/1963 Anstett 252/117 [75] Invenmr- Oldham 2,976,209 3/1961 Lindner 252/546 x England [73] Assignee: Colgate-Palmolive Company, New FOREIGN PATENTS 0R APPLICATIONS I York, N Y 1,077,470 7/1967 Great Britain 260/481 [22] Flled: 1972 Primary Examiner-Leon D. Rosdol [21] Appl. No.: 285,318 Assistant Examiner-Dennis L. Albrecht Attorney, Agent, or Firm-Herbert S. Sylvester [52] US. Cl 252/117, 252/546, 252/354,

252/355, 252/DIG. 16, 260/481 R 57 ABSTRACT [51] Int. CL... C07c 143/12, C1 1d 1/12, Clld 9/46 I [58] Field 01 Sea ch... 252/1 17, 121, 527, 546, 354, A detergent bar including a ma or amount of anhy- 252/3 5 5 DIG 260/481 R drous water-soluble higher fatty acid soap and a minor amount of a water-soluble synthetic detergent chosen [56] References Cited from the group including fatty ester amides of sul UNITED STATES PATENTS Pmsuccmlc 3,640,882 2/1972 Groves 252/121 6 Claims, N0 Drawings SOAP BARS The invention relates generally to detergent bars having improved curd dispering properties as well as good lathering performance. More specifically, the invention is concerned with detergent bars, comprising a combination of a soap and a curd dispersing synthetic detergent, that are firm, non-tacky and pleasant to use.

It is well known that when ordinary toilet soap is used in hard water, i.e., water with a relatively high concentration of magnesium and calcium metals, the formation and precipitation of an insoluble scum or curd usually results. This curd, commonly known as lime soap, includes coagulated, insoluble fatty acid salts and is commonly observed in wash basins or bathtubs as a scum that adheres to the walls as an unsightly ring.

It has been suggested that soap and a synthetic detergent having lime soap dispersing properties be combined in bar form to prevent the formation of the very undesirable lime soap curds. However, the use of large amounts of synthetic detergent in combination with soap, generally results in the impairment or elimination of desirable soap properties such as lathering performance, firmness and non-tackiness. Additionally, the inclusion of large amounts of synthetic detergent in soap bars usually results in manufacturing difficulties and a substantially increased cost.

In accordance with the invention, a new synthetic detergent is provided, which when combined with soap in predetermined amounts produces a combination bar exhibiting a substantially reduced tendency to form lime soap curds when used in hard water. Additionally, the new combination bars retain good lathering performance, are non-tacky and pleasant to use.

The kind of soap used in preparing the improved combination soap-detergent bar is not critical and should not be considered a limitation of the invention. Any of the water-soluble soaps, derived from animal or vegetable fatty acids, and formulated for industrial, household and toilet use may be employed. Watersoluble soaps such as the sodium, potassium and other suitable alkali metal or ammonium soap or soaps of nitrogen bases, such as triethanolamine, derived from fats and oils such as cottonseed oil, soybean oil, corn oil, olive oil, palm oil, palm kernel, lard, greases, fish oils and the like, as well as their hydrogenated derivatives; and mixtures thereof, that are properly blended to yield the desired soap quality may be used in formulating the soap portion of the new combination bars.

in accordance with the invention, the new detergent bar includes a synthetic detergent component of up to about 30 percent by weight. More specifically the synthetic detergent component of the improved bar includes fatty ester amides of sulphosuccinic acid having the following alternative structures:

wherein: M is chosen from those positive metals, and groups which produce water-soluble salts of the sulfosuccinate amide, including the alkali metals sodium and potassium, hydrogen, ammonium or organic bases such as ethanolamine, alkaloid, etc.

R, is hydrogen or a C to C saturated or unsaturated fatty chain;

R is a C, to C aliphatic chain; and

R is hydrogen or a C,, to C,,, saturated or unsaturated fatty chain, and

R, and R, cannot both be hydrogen.

Although the monoester derivative is preferred in practicing the invention, i.e., wherein R, is hydrogen; significant quantities of the diester as well as free alcohol and free alcohol amide can be present.

In further accordance with the invention, it is preferred to use sperm oil monoalkylolamide sulphosuccinate as the synthetic detergent ingredient of the new bars. Sperm oil monoethanolamide sulphosuccinate which is a mixture of components of the above described structure wherein M is sodium, R, is H, C H or C,,;H plus minor amounts of other fatty chains; R iS C2H4- and R3 is C15H29, C17H33 OI C19H37 plus minor amounts of other aliphatic chains is preferred. The foregoing sperm oil derivatives are mainly monoester but significant quantities of di-ester, free alcohol and free alkyl ethanolamide would be expected as well.

Sperm oil monoalkylolamide sulphosuccinates can be synthesized from sperm oil, which is R COOR, wherein R, is a C to C saturated or unsaturated fatty chain (mainly C,,,H,;, and C,,,H and R is a C to C saturated or unsaturated fatty chain (mainly C, H C I-I and C l'l as follows sperm oil is reacted with an alkylolamine of the general formula HOR -NH wherein R is C H C H or C.,H to give a fatty alkylolamide of the formula R CONHR Ol-l and a fatty alcohol, R,Ol-l. The'fatty alkylolamide and fatty alcohol mixture is reacted with maleic anhydride to give sperm oil monoalkylolamide maleate, which has the following structure:

fat charge to the kettle or other equipment for making the soap including the following:

Coconut Oil Castor Oil Palm Kernel Oil Groundnut Oil Babassu Oil Linseed Oil Palm Oil Cottonseed Oil Animal Fats sh Oils Olive Oil and hydrogenated versions of these Tallow Oil products, but tallow and coconut type oils Resin are preferred The caustic used to saponify the fat charge is prefera- -bly sodium hydroxide but it may be replaced in part by potassium hydroxide, e.g., up to about 15 percent if desired.

It is advantageousto include a preservative and/or a sequestrant in the soap to prevent the rancification of the free fatty acids. Among suitable preservatives and sequestrants are the following: 2-6 ditertiary butyl pcresol, tertiary butyl hydroxyanisole, Sopanox, triphenyl phosphite, stannic chloride magnesium silicate, Benztriazole and the alkali salts of ethylene diamine tetraacetic acid, hydroxyethylethylene diamine triacetic acid, diethylene triamine pentacetic acid and dihydroxyethyl glycine.

The usual steps for converting kettle soap into milled toilet bar form may be used for making the bars of the present invention which include crutching the neat soap phase with the predetermined proportion of synthetic detergent and other desired additives then drying the soap to a moisture content within the range of about 8 to 15 percent, preferably about 9 to 10 percent, mixing the dried soap in the form of dried ribbons, granules, or the like, in an amalagamator with other desired additives such as colors, perfumes, glycerine, lanolin, cold cream, etc., milling the mixture, plodding the milled chips to form a long, continuous bar, cutting the bar into tablet or cake lengths and pressing or stamping the tablet or cake which may then be wrapped or not, as desired.

Suitable soap making processes that may be used to prepare soap for use in the present process include the usual kettle soap making process, continuous saponification processes in which saponification is effected with aqueous alkali and heat, the resultant mixture being washed and fitted to obtain a neat soap either continuously or by use of a kettle for the fitting and optionally one or more washing stages, and neutralization processes for fatty acids derived by hydrolysis of fats and oils.

The kettle process of making soap is well known to those skilled in the soap making art so it will be disclosed here only in general outline since it does not form part of the present invention. A typical kettle process includes the following stages:

1. Killing or saponification stage 2. Change stage 3. Washing stage 4. Fitting or pitching stage In the first or saponification stage, the fatty material chosen for the particular soap to be produced, e.g., fats and oils which are glyceryl esters of fatty acids, is heated with aqueous caustic solution to effect substantial conversion of the fatty material to glycerine and fatty acid salts of the alkali metal or metals present in the caustic solution. For toilet bars, sodium soaps are generally preferred, but in some cases caustic potash may be used with caustic solution. Potassium soaps are softer than sodium soaps of the same fatty acid content and, therfore, the content of potassium fatty acid salts is somewhat limited in proportion to the sodium fatty acids salts in order to have a soap that works up well into bar form in conventional soap-making machinery. Generally, the caustic solution used in the killing stage is obtained in whole or in part from the change stage of another batch. The extent of saponification in the killing stage is not critical and may vary from as low as about 80 percent to almost complete saponification.

In the change stage, which may take place in one or more separate operations, salt is added to the reaction mixture in sufiicient concentration to effect precipitation of the soap from the solution. The salt used may be fresh salt or salt recovered from the purification of the glycerine, or a mixture of both. Generally, boiling is continued for a short time after addition of the salt and if the saponification is incomplete in the killing stage caustic may be included with the salt to complete the saponification during this boil. The mass is then settled, during which the less dense soap rises to the top and the spent lye containing the bulk of the glycerine and electrolyte sinks to the bottom. When the settling is complete the lye is drawn off and sent to the glycerine plant for recovery of the glycerine, salt, etc.

The washing stage has as its object the more complete removal of glycerine, which may be as much as 0.5 percent of the weight of the soap layer left after drawing off the lye, and the complete saponification of the fat charge. In general, a washing operation consists of closing the soap by adding water and boiling vigorously, usually with open steam, and then adding salt and/or caustic to grain the soap and permit settling agains into an aqueous lower layer and an upper grained soap layer. Where caustic is used in the washing operation, it is sometimes called a strengthening change and the lye settled is not fully spent and may be used as the caustic solution in the killing stage of another batch of fatty material. The washing operation also removes further amounts of impurities that may have been present in the original charge.

The fitting or pitching stage has for its objective the separation of a neat soap phase from a nigre phase and it is effected by again closing the soap by the addition of water and boiling. The water addition is carefully done so as to reach a final stage where the electrolyte content of the mixture is sufficient to dissolve part of the soap but not all of it. On settling, the dissolved soap sinks to the bottom and forms the nigre while the undissolved soap rises to the top as neat soap. The neat soap may then be pumped from the kettle for further processing.

A typical composition of the withdrawn neat soap is approximately'63 percent total fatty acids, with a maximum of about 0.14 percent caustic calculated as Na O and a maximum of about 0.6 percent sodium chloride, with water at about the 30-32 percent level. The water content is typically reduced to approximately 10 percent during further processing.

Soap of similar composition may be obtained by other soap making processes, such as the continuous and neutralization process referred to above. These processes are also well known to workers of ordinary skill in this art and need not be further described.

In further accordance with the invention, the new combination bars comprise a major portion of soap and a minor portion of synthetic detergent by weight. A combination of up to about 30 percent by weight synthetic detergent and not less than about percent by weight soap is preferred. Of course, minor amounts of materials such as pigments, perfumes, sequestrants, etc., that are commonly employed in toilet soap bars may also be included in the new combination bars. Combination bars formulated with these materials and within these limits provide excellent lime soap dispersing characteristics without adversely affecting the lathering performance and feel of the final bar.

Suitable combination bars in accordance with the invention can be prepared as follows (all percentages are by weight):

Sperm oil monoethanolamide sulphosuccinate containing about 40 percent of active ingredient is mixed with a soap base containing about 63 percent total fatty acids and 32 percent moisture, in the following proportions. The soap base also includes small amounts of preservatives and sequestrants in accordance with principles well known in the art.

Example number: 1 2 3 4 5 Soap base Sperm oil Monoethanolamide sulphosuccinate (40%) The soap base-synthetic detergent mixtures are then dried to about a percent moisture content. The dried mixtures have the following approximate compositions:

The dried, soap base-synthetic detergent mixtures are then process by conventional soap making techniques into bar form. A small amount of titanium dioxide, about 0.2 percent, and perfumes and colorants may also be added during the processing of the soap base-synthetic detergent mass into bars.

The soap base-synthetic detergent combination bars of the foregoing Examples l-5 exhibit lathering characteristics, soil removal properties, mildness and tackiness, not significantly different from similar soap bars formulated without the sperm oil monoethanolamide additive. However, the new combination bars exhibit a very marked reduction in the amount of lime soap curd formed when the bar is used in calcium and magnesium hard water. Variation of the amount of synthetic detergent in the new bar from nil to about 30 percent results in progressively greater lime soap dispersing properties without any significant effect on the lather, soil removing, mildness and other desirable characteristics of the soap portion of the bar.

Panel tests on hand washing performance of combination bars according to the foregoing formulations with the amount of synthetic detergent being nil, 6.3, 12.3, 18.1, 23.7 and 29.0 percent showed no significant difference between the bars for speed and formation of lather, amount of lather, stability of lather and creaminess of lather. All of the foregoing bars were found to be firm, non-tacky and pleasant to use.

Although the present invention has been described and illustrated with reference to certain specific embodiments, it is to be understood that variations and modifications can be made without departing from the spirit and scope of the invention as defined in the following claims.

I claim: 1. An improved detergent bar consisting essentially of:

A. a major amount of an anhydrous water higher fatty acid soap, and B. a lime soap dispersing agent chosen from the group consisting of:

M-SO, H cooR,NH coR,. H COOR MHCOR wherein m is chosen from the group consisting of sodium, potassium hydrogen, ammonium and ethanolamine, R is chosen from the group consisting of hydrogen and C to C saturated and unsaturated fatty chains, R is chosen from the group consisting of C to C aliphatic hydrocarbon chains, and R is chosen from the group consisting of C to C saturated and unsaturated fatty chains, said lime soap is dispersing agent being present in an amount ranging from a finite quantity sufficient to impart lime soap dispersing properties to the detergent bar composition up to about 30 percent by weight of said bar.

2. The improved detergent bar of claim 1 wherein said major amount of soap is at least 60 percent by weight of the bar.

3. The improved detergent bar of claim 1 wherein said lime soap dispersing agent is a sperm oil monoalkylolamide sulphosuccinate.

4. The improved detergent bar of claim 1 wherein said sperm oil monoalkylolamide sulphosuccinate is sperm oil monoethanolamide sulphosuccinate.

5. The improved detergent bar of claim 1 wherein the water soluble soap is a sodium soap of fatty acids derived from a mixture containing 50 to percent tallow and 30 to 50 percent coconut or palm kernel oil.

6. The improved detergent bar claim 1 having a water content of 10 percent by weight of the bar. 

2. The improved detergent bar of claim 1 wherein said major amount of soap is at least 60 percent by weight of the bar.
 3. The improved detergent bar of claim 1 wherein said lime soap dispersing agent is a sperm oil monoalkylolamide sulphosuccinate.
 4. The improved detergent bar of claim 1 wherein said sperm oil monoalkylolamide sulphosuccinate is sperm oil monoethanolamide sulphosuccinate.
 5. The improved detergent bar of claim 1 wherein the water soluble soap is a sodium soap of fatty acids derived from a mixture containing 50 to 70 percent tallow and 30 to 50 percent coconut or palm kernel oil.
 6. The improved detergent bar claim 1 having a water content of 10 percent by weight of the bar. 